Jean-Mathias Grießmeier
University of Orléans
Polarization (waves)Low frequencyPulsarCosmic rayPhysicsAstronomyRadio astronomyRadio telescopeExoplanetFluxLOFARTelescopeAstrophysicsMaserPlanetJupiterCoronal mass ejectionSkyRadio frequencyAstrobiology
90Publications
28H-index
2,833Citations
Publications 91
Newest
#1Jake D. TurnerH-Index: 15
#2Philippe ZarkaH-Index: 45
Last. Imke de PaterH-Index: 36
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#1Jake D. Turner (Cornell University)H-Index: 15
#2Philippe ZarkaH-Index: 45
Last. Imke de PaterH-Index: 36
view all 11 authors...
Observing planetary auroral radio emission is the most promising method to detect exoplanetary magnetic fields, the knowledge of which will provide valuable insights into the planet's interior structure, atmospheric escape, and habitability. We present LOFAR-LBA circularly polarized beamformed observations of the exoplanetary systems 55 Cancri, \upsilonAndromedae, and \tauBootis. We tentatively detect circularly polarized bursty emission from the \tauBootis system in the range 14-21 MHz...
2 CitationsSource
#1J. Y. DonnerH-Index: 3
Last. C. VocksH-Index: 2
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Radio pulses from pulsars are affected by plasma dispersion, which results in a frequency-dependent propagation delay. Variations in the magnitude of this effect lead to an additional source of red noise in pulsar timing experiments, including pulsar timing arrays that aim to detect nanohertz gravitational waves. We aim to quantify the time-variable dispersion with much improved precision and characterise the spectrum of these variations. We use the pulsar timing technique to obtain highly preci...
1 CitationsSource
#1L. BondonneauH-Index: 4
Last. Andrew LyneH-Index: 74
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3 CitationsSource
#1L. BondonneauH-Index: 1
Last. Andrew LyneH-Index: 74
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1 CitationsSource
#1Baptiste Cecconi (University of Orléans)H-Index: 34
#2Alan Loh (CNRS: Centre national de la recherche scientifique)H-Index: 2
Last. Philippe Zarka (University of Orléans)H-Index: 1
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MASER (Measurements, Analysis, and Simulation of Emission in the Radio range) is a comprehensive infrastructure dedicated to time-dependent low frequency radio astronomy (up to about 50 MHz). The main radio sources observed in this spectral range are the Sun, the magnetized planets (Earth, Jupiter, Saturn), and our Galaxy, which are observed either from ground or space. Ground observatories can capture high resolution data streams with a high sensitivity. Conversely, space-borne instruments can ...
#1D. Michilli (McGill University)H-Index: 15
#2C. G. BassaH-Index: 33
Last. Patrick Weltevrede (University of Manchester)H-Index: 52
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We are using the LOw-Frequency ARray (LOFAR) to perform the LOFAR Tied-Array All-Sky (LOTAAS) survey for pulsars and fast transients. Here, we present the astrometric and rotational parameters of 20 pulsars discovered as part of LOTAAS. These pulsars have regularly been observed with LOFAR at 149 MHz and the Lovell telescope at 1532 MHz, supplemented by some observations with the Lovell telescope at 334 MHz and the Nancay Radio Telescope at 1484 MHz. Timing models are calculated for the 20 pulsa...
1 CitationsSource
#1P. ZarkaH-Index: 10
#2Di LiH-Index: 46
Last. Gregg Hallinan (California Institute of Technology)H-Index: 19
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We briefly review the various proposed scenarios that may lead to nonthermal radio emissions from exoplanetary systems (planetary magnetospheres, magnetosphere-ionosphere and magnetosphere-satellite coupling, and star-planet interactions), and the physical information that can be drawn from their detection. The latter scenario is especially favorable to the production of radio emission above 70 MHz. We summarize the results of past and recent radio searches, and then discuss FAST characteristics...
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\textit{Context.}The magnetized Solar System planets are strong radio emitters and theoretical studies suggest that the radio emission from nearby exoplanets in close-in orbits could reach intensity levels 10^{3}-10^{6}times higher than Jupiter's decametric emission. Detection of exoplanets in the radio domain would open up a brand new field of research, however, currently there are no confirmed detections at radio frequencies. \textit{Aims.}We investigate the radio emission from Jupite...
1 CitationsSource
#1J. Y. Donner (MPG: Max Planck Society)H-Index: 3
#2Joris P. W. Verbiest (MPG: Max Planck Society)H-Index: 46
Last. Arpad MiskolcziH-Index: 12
view all 14 authors...
Context. High-precision pulsar-timing experiments are affected by temporal variations of the dispersion measure (DM), which are related to spatial variations in the interstellar electron content and the varying line of sight to the source. Correcting for DM variations relies on the cold-plasma dispersion law which states that the dispersive delay varies with the squared inverse of the observing frequency. This may, however, give incorrect measurements if the probed electron content (and therefor...
19 CitationsSource
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